Projector

ABSTRACT

A projector includes a laser source, a light modulation element configured to modulate light emitted from the laser source in accordance with image information, and a light transmissive member disposed in a light path between the laser source and the light modulation element, and configured to transmit the light emitted from the laser source, wherein the laser source and the light modulation element are bonded to the light transmissive member, the laser source includes a substrate, and a laminated structure provided to the substrate, and having a light emitting layer configured to emit light, and the laminated structure constitutes a photonic crystal structure configured to confine the light emitted by the light emitting layer in an in-plane direction of the substrate, and emit the light emitted by the light emitting layer in a normal direction of the substrate.

This is a continuation patent application of U.S. application Ser. No.16/728,184, filed Dec. 27, 2019, which is based on, and claims priorityfrom JP Application Serial Number 2018-247172, filed Dec. 28, 2018, thedisclosures of which are hereby expressly incorporated by referenceherein in their entireties.

BACKGROUND 1. Technical Field

The present disclosure relates to a projector.

2. Related Art

There has been put into practical use a projector for illuminating alight modulation element such as a liquid crystal light valve with thelight emitted from a light source, and then projecting the image lightformed by the light modulation element on a screen or the like tothereby perform display.

In, for example, International Publication No. WO 99/49358 (Document 1),there is described a projector for making the light emitted from an LD(Laser Diode) array constituted by semiconductor lasers enter atransmissive liquid crystal panel.

However, in the projector described in Document 1, since the lightemitted from the LD array is diffused, there is disposed a lens arrayfor collimating the light emitted from the LD array between the LD arrayand the transmissive liquid crystal panel. Since the lens array needs tobe disposed at a distance from the LD array and the transmissive liquidcrystal panel, in the projector described in Document 1, it is difficultto achieve reduction in size.

SUMMARY

A projector according to an aspect of the present disclosure includes alaser source, a light modulation element configured to modulate lightemitted from the laser source in accordance with image information, anda light transmissive member disposed in a light path between the lasersource and the light modulation element, and configured to transmit thelight emitted from the laser source, wherein the laser source and thelight modulation element are bonded to the light transmissive member,the laser source includes a substrate, and a laminated structureprovided to the substrate, and having a light emitting layer configuredto emit light, and the laminated structure constitutes a photoniccrystal structure configured to confine the light emitted by the lightemitting layer in an in-plane direction of the substrate, and emit thelight emitted by the light emitting layer in a normal direction of thesubstrate.

In the projector according to the aspect, the light transmissive membermay be a radiator plate configured to radiate heat of the laser source.

In the projector according to the aspect, the light transmissive membermay be a polarization element.

In the projector according to the aspect, the light transmissive membermay be a polarization split element.

In the projector according to the aspect, the light transmissive membermay be a total-reflection prism.

A projector according to an aspect of the present disclosure includes alaser source, and a light modulation element configured to modulatelight emitted from the laser source in accordance with imageinformation, wherein the laser source and the light modulation elementare bonded to each other, the laser source includes a substrate, and alaminated structure provided to the substrate, and having a lightemitting layer configured to emit light, and the laminated structureconstitutes a photonic crystal structure configured to confine the lightemitted by the light emitting layer in an in-plane direction of thesubstrate, and emit the light emitted by the light emitting layer in anormal direction of the substrate.

A projector according to an aspect of the present disclosure includes alaser source, a light modulation element configured to modulate lightemitted from the laser source in accordance with image information, anda radiator plate disposed between the laser source and the lightmodulation element, and configured to radiate heat of the laser source,wherein the laser source and the light modulation element are bonded tothe radiator plate, the radiator plate is provided with a through holethrough which the light emitted from the laser source passes, the lasersource includes a substrate, and a laminated structure provided to thesubstrate, and having a light emitting layer configured to emit light,and the laminated structure constitutes a photonic crystal structureconfigured to confine the light emitted by the light emitting layer inan in-plane direction of the substrate, and emit the light emitted bythe light emitting layer in a normal direction of the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically showing a projector according to afirst embodiment.

FIG. 2 is a diagram schematically showing a display device of theprojector according to the first embodiment.

FIG. 3 is a diagram schematically showing a light modulation element ofthe projector according to the first embodiment.

FIG. 4 is a diagram schematically showing a laser source of theprojector according to the first embodiment.

FIG. 5 is a diagram schematically showing a display device of aprojector according to a first modified example of the first embodiment.

FIG. 6 is a diagram schematically showing a display device of aprojector according to a second modified example of the firstembodiment.

FIG. 7 is a diagram schematically showing a display device of aprojector according to a third modified example of the first embodiment.

FIG. 8 is a diagram schematically showing a display device of aprojector according to a fourth modified example of the firstembodiment.

FIG. 9 is a diagram schematically showing a light modulation element ofa projector according to a fourth modified example of the firstembodiment.

FIG. 10 is a diagram schematically showing a laser source of a projectoraccording to a fifth modified example of the first embodiment.

FIG. 11 is a diagram schematically showing a projector according to asecond embodiment.

FIG. 12 is a diagram schematically showing a display device of theprojector according to the second embodiment.

FIG. 13 is a diagram schematically showing a projector according to athird embodiment.

FIG. 14 is a diagram schematically showing a laser source of theprojector according to the third embodiment.

FIG. 15 is a diagram schematically showing a projector according to amodified example of the third embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Some preferred embodiments of the present disclosure will hereinafter bedescribed in detail using the accompanying drawings. It should be notedthat the embodiments described below do not unreasonably limit thecontents of the present disclosure as set forth in the appended claims.Further, all of the constituents described hereinafter are notnecessarily essential elements of the present disclosure.

1. First Embodiment

1.1. Projector

Firstly, a projector according to a first embodiment will be explainedwith reference to the accompanying drawings. FIG. 1 is a diagramschematically showing the projector 1000 according to the firstembodiment.

As shown in FIG. 1 , the projector 1000 has, for example, displaydevices 10R, 10G, and 10B, polarization elements 20, a colored lightcombining prism 30, and a projection lens 40. Here, FIG. 2 is a diagramschematically showing the display device 10R.

As shown in FIG. 2 , the display device 10R has, for example, a lasersource 100, a light modulation element 200, and a light transmissivemember 300. It should be noted that in FIG. 2 , the laser source 100 isillustrated in a simplified manner for the sake of convenience.

The laser source 100 emits a laser beam. The laser source 100 emits redlight. In the illustrated example, a radiator fin 150 is coupled to thelaser source 100. The radiator fin 150 radiates the heat generated inthe laser source 100. Thus, it is possible to enhance the emissionefficiency of the laser source 100.

The light modulation element 200 modulates the light emitted from thelaser source 100 in accordance with image information. The lightmodulation element 200 is, for example, a transmissive liquid crystallight valve for transmitting the light emitted from the laser source100. The projector 1000 is an LCD (liquid crystal display) projector.Here, FIG. 3 is a diagram schematically showing the light modulationelement 200, and is a diagram of the light modulation element 200 viewedfrom the incident side of the light emitted from the laser beam 100.

As shown in FIG. 2 and FIG. 3 , the light modulation element 200 isconfigured including, for example, an opposed substrate 202, a TFT (ThinFilm Transistor) substrate 204, and a dust-proof substrate 206, and hasa liquid crystal layer having a light modulation function between theopposed substrate 202 and the TFT substrate 204 although not shown inthe drawings. In the example shown in FIG. 3 , a display area 200 alocated in a central part and having a rectangular shape is provided,and the light having entered the display area 200 a is modulated to formimage light.

As shown in FIG. 2 , the light transmissive member 300 is disposed in alight path of the light emitted from the laser source 100 between thelaser source 100 and the light modulation element 200. In theillustrated example, the light transmissive member 300 is disposedbetween the laser source 100 and the light modulation element 200. Thelaser source 100 and the light modulation element 200 are bonded to thelight transmissive member 300.

Here, “bonding” includes when coupled to each other with an adhesive,and when coupled to each other with interface bonding. In other words,the expression that “the laser source 100 and the light modulationelement 200 are bonded to the light transmissive member 300” includeswhen the laser source 100 and the light modulation element 200 arecoupled to the light transmissive member 300 with an adhesive, and whenthe laser source 100 and the light modulation element 200 is coupled tothe light transmissive member 300 with the interface bonding. The“interface bonding” is to make the interfaces smooth and clean to havecontact with each other to thereby be coupled to each other with atomsdiffused across the interfaces having contact with each other.

In the illustrated example, the laser source 100 and the lightmodulation element 200 are coupled to the light transmissive member 300with an adhesive 310. The adhesive 310 transmits the light emitted fromthe laser source 100. It is preferable for the refractive index of theadhesive 310 to be close to the refractive index of a member havingcontact with the adhesive 310 of the laser source 100, the refractiveindex of a member having contact with the adhesive 310 of the lightmodulation element 200, and the refractive index of a member havingcontact with the adhesive 310 of the light transmissive member 300.Thus, it is possible to reduce the light loss generated on the interfacebetween the adhesive 310 and the member having contact with the adhesive310. As the adhesive 310, it is possible to use, for example, an epoxyadhesive (the refractive index of about 1.55 through 1.65) and asilicone adhesive (the refractive index of about 1.40 through 1.47).

It is also possible for the adhesive 310 to include a metal filler.Thus, it is possible to increase the thermal conductivity of theadhesive 310, and thus, it is possible to efficiently radiate the heatgenerated in the laser source 100. It should be noted that the adhesive310 for coupling the laser source 100 and the light transmissive member300 to each other and the adhesive 310 for coupling the light modulationelement 200 and the light transmissive member 300 to each other can bethe same in type, or can also be different in type from each other.

The light transmissive member 300 has a first surface 302 and a secondsurface 304. The laser source 100 is bonded to the first surface 302.Specifically, a second electrode 124 of the laser source 100 shown inFIG. 4 described later is bonded to the first surface 302. As shown inFIG. 2 , the light modulation element 200 is bonded to the secondsurface 304. Specifically, the opposed substrate 202 of the lightmodulation element 200 is bonded to the second surface 304. In theillustrated example, the first surface 302 and the second surface 304face to directions opposite to each other.

The light transmissive member 300 is, for example, a polarizationelement. The polarization element adjusts the polarization direction ofthe light emitted from the laser source 100. Specifically, thepolarization element is an optical element for transmitting only thelinearly polarized light in a specific direction. Therefore, when thelight emitted from the laser source 100 has a polarized nature, it isdesirable to dispose the polarization element so that the polarizingaxis of the emitted light and the transmission axis of the polarizationelement coincide with each other. It is possible to uniform thepolarization direction of the light emitted from the laser source 100due to the polarization element. As the polarization element, it ispossible to use, for example, a polarization element of an inorganictype such as a wire grid polarizer, and a polarization element of anorganic type such as a film polarizer using a stretch orientation film.When adopting a resin film-base polarizer, it is also possible to usethe polarizer directly, but it is possible to more firmly and morestably fix the laser source 100 and the light modulation element 200when using the polarizer stuck to a substrate made of sapphire, glass,or the like. It should be noted that the polarization element of theinorganic type is preferable taking the heat resistance and the lightresistance into consideration.

The display devices 10G, 10B shown in FIG. 1 each have the laser source100, the light modulation element 200, and the light transmissive member300 similarly to the display device 10R. It should be noted that thelaser source 100 of the display device 10G emits the green light.Further, the laser source 100 of the display device 10B emits the bluelight.

As shown in FIG. 1 , the polarization elements 20 are respectivelydisposed between the display device 10R and the colored light combiningprism 30, between the display device 10G and the colored light combiningprism 30, and between the display device 10B and the colored lightcombining prism 30. The polarization elements 20 function as analyzerswith respect to the light emitted from the display devices 10R, 10B, and10B. The light emitted from the polarization elements 20 enters thecolored light combining prism 30.

The colored light combining prism 30 combines the light emitted from thedisplay device 10R, the light emitted from the display device 10G, andthe light emitted from the display device 10B with each other. Thecolored light combining prism 30 is, for example, a cross dichroic prismwhich is formed by bonding four rectangular prisms to each other, and isprovided with a dielectric multilayer film for reflecting the red lightand a dielectric multilayer film for reflecting the blue light disposedon the inside surfaces thereof so as to form a crisscross.

The projection lens 40 projects the light combined by the colored lightcombining prism 30 on a screen not shown. An image enlarged is displayedon the screen.

Then, a configuration of the laser source 100 will be described. FIG. 4is a cross-sectional view schematically showing the laser source 100. Asshown in FIG. 4 , the laser source 100 has, for example, a substrate102, a laminated structure 103 disposed on the substrate 102, a firstelectrode 122, a second electrode 124, and an interconnection 126. Thelaminated structure 103 has a reflecting layer 104, a buffer layer 106,a photonic crystal structure 108, and a semiconductor layer 120.

The substrate 102 is, for example, an Si substrate, a GaN substrate, ora sapphire substrate.

The reflecting layer 104 is disposed on the substrate 102. Thereflecting layer 104 is, for example, a DBR (distributed Braggreflector) layer. The reflecting layer 104 is, for example, what isobtained by alternately stacking AlGaN layers and GaN layers on oneanother or what is obtained by alternately stacking AlInN layers and GaNlayers on one another. The reflecting layer 104 reflects the lightgenerated by a light emitting layer 114 of each of columnar parts 110 ofthe photonic crystal structure 108 toward the second electrode 124.

It should be noted that “upward” denotes a direction of getting awayfrom the substrate 102 viewed from the light emitting layer 114 in astacking direction (hereinafter also referred to simply as the “stackingdirection”) of a semiconductor layer 112 and the light emitting layer114 in each of the columnar parts 110, and “downward” denotes adirection of getting closer to the substrate 102 viewed from the lightemitting layer 114 in the stacking direction.

The buffer layer 106 is disposed on the reflecting layer 104. The bufferlayer 106 is a layer made of semiconductor such as an Si-doped n-typeGaN layer. In the illustrated example, on the buffer layer 106, there isdisposed a mask layer 128 for growing the columnar parts 110. The masklayer 128 is, for example, a silicon oxide layer or a silicon nitridelayer.

The photonic crystal structure 108 is disposed on the buffer layer 106.The photonic crystal structure 108 has the columnar parts 110 and lightpropagation layers 118. The laminated structure 103 constitutes thephotonic crystal structure 108. In the illustrated example, the columnarparts 110 and the light propagation layers 118 of the laminatedstructure 103 constitute the photonic crystal structure 108.

The photonic crystal structure 108 can develop an effect of the photoniccrystal, and the light emitted by the light emitting layers 114 of thephotonic crystal structure 108 is confined in an in-plane direction ofthe substrate 102, and is emitted in a normal direction of the substrate102. Here, the “in-plane direction of the substrate 102” denotes adirection perpendicular to the stacking direction. The “normal directionof the substrate 102” denotes the stacking direction. The laser source100 is a photonic crystal laser having the photonic crystal structure108.

The columnar parts 110 are disposed on the buffer layer 106. A planarshape of the columnar part 110 is a polygonal shape such as a regularhexagon, a circle, or the like. The diametrical size of the columnarpart 110 is, for example, in an nm-order range, and is specifically nosmaller than 10 nm and no larger than 500 nm. The size in the stackingdirection of the columnar part 110 is, for example, no smaller than 0.1μm and no larger than 5 μm.

It should be noted that when the planar shape of the columnar part 110is a circle, the “diametrical size” denotes the diameter of the circle,and when the planar shape of the columnar part 110 is a polygon, the“diametrical size” denotes the diameter of the minimum circle includingthe polygon inside, namely the minimum enclosing circle. Further, the“planar shape” denotes a shape viewed from the stacking direction.

The number of the columnar parts 110 disposed is more than one. Aninterval between the columnar parts 110 adjacent to each other is, forexample, no smaller than 1 nm and no larger than 500 nm. The columnarparts 110 are periodically disposed in a predetermined direction at apredetermined pitch. The plurality of columnar parts 110 is disposed soas to form, for example, a triangular grid or a quadrangular grid whenviewed from the stacking direction.

The columnar parts 110 each have the semiconductor layer 112, the lightemitting layer 114, and a semiconductor layer 116.

The semiconductor layer 112 is disposed on the buffer layer 106. Thesemiconductor layer 112 is, for example, the Si-doped n-type GaN layer.

The light emitting layer 114 is disposed on the semiconductor layer 112.The light emitting layer 114 is disposed between the semiconductor layer112 and the semiconductor layer 116. The light emitting layer 114 has aquantum well structure constituted by, for example, a GaN layer and anInGaN layer. The light emitting layer 114 is a layer capable of emittinglight in response to injection of an electrical current.

The semiconductor layer 116 is disposed on the light emitting layer 114.The semiconductor layer 116 is a layer different in conductivity typefrom the semiconductor layer 112. The semiconductor layer 116 is, forexample, an Mg-doped p-type GaN layer. The semiconductor layers 112, 116are cladding layers having a function of confining the light in thelight emitting layer 114.

The light propagation layers 118 are each disposed between the columnarparts 110 adjacent to each other. In the illustrated example, the lightpropagation layers 118 are disposed on the mask layer 128. Therefractive index of the light propagation layer 118 is lower than, forexample, the refractive index of the light emitting layer 114. The lightpropagation layer 118 is, for example, a silicon oxide layer, analuminum oxide layer, or a titanium oxide layer. The light generated inthe light emitting layer 114 can propagate through the light propagationlayer 118.

In the laser source 100, the p-type semiconductor layer 116, the lightemitting layer 114 with no impurity doped, and the n-type semiconductorlayer 112 constitute a pin diode. The semiconductor layers 112, 116 arelayers larger in bandgap than the light emitting layer 114. In the lasersource 100, when applying a forward bias voltage of the pin diodebetween the first electrode 122 and the second electrode 124 to inject acurrent, there occurs recombination of electrons and holes in the lightemitting layer 114. The recombination causes light emission. The lightgenerated in the light emitting layer 114 propagates through the lightpropagation layer 118 in the in-plane direction of the substrate 102 dueto the semiconductor layers 112, 116 to form a standing wave due to theeffect of the photonic crystal in the photonic crystal structure 108,and is confined in the in-plane direction of the substrate 102. Thelight thus confined causes laser oscillation with the gain in the lightemitting layer 114. In other words, the light generated in the lightemitting layer 114 oscillates in the in-plane direction of the substrate102 due to the photonic crystal structure 108 to cause the laseroscillation. Then, positive first-order diffracted light and negativefirst-order diffracted light proceed in the stacking direction as alaser beam.

The laser beam proceeding toward the reflecting layer 104 out of thelaser beam having proceeded in the stacking direction is reflected bythe reflecting layer 104, and proceeds toward the second electrode 124.Thus, it is possible for the laser source 100 to emit the light from thesecond electrode 124 side.

The radiation angle of the light emitted from the laser source 100 issmaller than 2°, and is smaller compared to, for example, anedge-emission type semiconductor laser and a VCSEL (Vertical CavitySurface Emitting Laser). Further, even when, for example, there is adefect in one columnar part 110, since the standing wave is formed in adirection perpendicular to the stacking direction, it is possible tocompensate for the defect to emit the light high in uniformity of theintensity.

The semiconductor layer 120 is disposed on the photonic crystalstructure 108. The semiconductor layer 120 is, for example, an Mg-dopedp-type GaN layer.

The first electrode 122 is disposed on the buffer layer 106. It is alsopossible for the buffer layer 106 to have ohmic contact with the firstelectrode 122. In the illustrated example, the first electrode 122 iselectrically coupled to the semiconductor layer 112 via the buffer layer106. The first electrode 122 is one of the electrodes for injecting thecurrent into the light emitting layer 114. As the first electrode 122,there can be used, for example, what is obtained by stacking a Ti layer,an Al layer, and an Au layer in this order from the buffer layer 106side.

The second electrode 124 is disposed on the semiconductor layer 120. Itis also possible for the semiconductor layer 120 to have ohmic contactwith the second electrode 124. The second electrode 124 is electricallycoupled to the semiconductor layer 116. In the illustrated example, thesecond electrode 124 is electrically coupled to the semiconductor layer116 via the semiconductor layer 120. The second electrode 124 is theother of the electrodes for injecting the current into the lightemitting layer 114. As the second electrode 124, for example, ITO(Indium Tin Oxide) is used.

The interconnection 126 is coupled to the second electrode 124. Theinterconnection 126 is electrically separated from the buffer layer 106.The material of the interconnection 126 is, for example, copper,aluminum, or gold.

It should be noted that although the light emitting layer 114 of theInGaN type is described above, any types of material capable of emittinglight in response to an electrical current injected in accordance withthe wavelength of the light emitted can be used as the light emittinglayer 114. It is possible to use semiconductor materials such as anAlGaN type, an AlGaAs type, an InGaAs type, an InGaNAsP type, an InPtype, a GaP type or an AlGaP type. Further, it is also possible tochange the size and the pitch of the arrangement of the columnar parts110 in accordance with the wavelength of the light emitted.

Further, although the photonic crystal structure 108 has the columnarparts 110 disposed periodically in the above description, it is alsopossible to have hole parts disposed periodically in order to developthe photonic crystal effect.

Here, as shown in FIG. 2 , it is also possible for the shape of thelight emitting section 100 a of the laser source 100 and the shape ofthe display area 200 a of the light modulation element 200 to besubstantially the same when viewed from the proceeding direction of thelight emitted from the laser source 100. It is also possible for theshape of the light emitting section 100 a and the shape of the displayarea 200 a to be the same. It is also possible for the size of the lightemitting section 100 a and the size of the display area 200 a to besubstantially the same. It is also possible for the size of the lightemitting section 100 a and the size of the display area 200 a to be thesame. It should be noted that the light emitting section 100 a is a partfor emitting light, and when the laser source 100 is a photonic crystallaser provided with the columnar parts 110 each having the lightemitting layer 114, the light emitting section 100 a is the photoniccrystal structure 108. Further, the “proceeding direction of the light”corresponds to the stacking direction.

Then, a method of manufacturing the laser source 100 will be described.

As shown in FIG. 4 , the reflecting layer 104 and the buffer layer 106are grown epitaxially in this order on the substrate 102. As the methodof growing the layer epitaxially, there can be cited, for example, anMOCVD (Metal Organic Chemical Vapor Deposition) method and an MBE(Molecular Beam Epitaxy) method.

Then, the mask layer 128 is formed on the buffer layer 106 using theMOCVD method or the MBE method. Then, the semiconductor layer 112, thelight emitting layer 114, and the semiconductor layer 116 are grownepitaxally in this order on the buffer layer 106 using the mask layer128 as a mask. As the method of growing the layers epitaxially, therecan be cited, for example, the MOCVD method and the MBE method. Due tothe present process, it is possible to form the columnar parts 110.Then, the light propagation layer 118 is formed between the columnarparts 110 adjacent to each other using a spin coat method or the like.Due to the present process, it is possible to form the photonic crystalstructure 108.

Then, the semiconductor layer 120 is formed on the columnar parts 110and the light propagation layer 118 using, for example, the MOCVD methodor the MBE method.

Subsequently, the first electrode 122 and the second electrode 124 areformed using, for example, a vacuum evaporation method. Then, theinterconnection 126 is formed using, for example, a sputtering method ora plating method.

Due to the process described hereinabove, it is possible to form thelaser source 100.

The projector 1000 has, for example, the following features.

In the projector 1000, the light transmissive member 300 fortransmitting the light emitted from the laser source 100 is disposed inthe light path between the laser source 100 and the light modulationelement 200, and the laser source 100 and the light modulation element200 are bonded to the light transmissive member 300. Therefore, in theprojector 1000, it is possible to make the distance between the lasersource 100 and the light modulation element 200 smaller to therebyachieve reduction in size compared to when the laser source and thelight transmissive member are separated from each other, and at the sametime, the light modulation element and the light transmissive member areseparated from each other. Further, reduction in weight can be achieved.In the projector 1000, since the laminated structure 103 constitutes thephotonic crystal structure 108 which confines the light emitted by thelight emitting layer 114 in the in-plane direction of the substrate 102and emits the light in the normal direction of the substrate 102, thelight emitted from the laser source 100 is small in radiation angle andhigh in uniformity of intensity as described above. Therefore, since itis not required to dispose a collimating lens for collimating the lightemitted and a fly-eye lens for enhancing the uniformity of theintensity, it is possible to bond the laser source 100 and the lightmodulation element 200 to the light transmissive member 300.

Further, in the projector 1000, since there is no need to dispose a lensarray such as a fly-eye lens, it is possible to efficiently illuminatethe light modulation element 200. When the lens array is disposed,taking a shape error of the lens, an optical aberration generated in thelens, and an arrangement error of the lens array into consideration, thelight modulation element is usually illuminated with light having alarger cross-sectional size compared to the display area of the lightmodulation element. In this case, since it results in that the lightentering an area outside the display area of the light modulationelement is generated, the use efficiency of the light is low. In theprojector 1000, since it is possible to dispose the laser source 100 andthe light modulation element 200 closely to each other, and further itis not required to dispose the lens array, it is possible to make thesize of the light emitting section 100 a close to the size of thedisplay area 200 a to thereby efficiently illuminate the lightmodulation element 200. As a result, an increase in luminance can beachieved. Further, reduction in size can be achieved.

Further, in the projector 1000, since the laser source 100 and the lightmodulation element 200 are bonded to the light transmissive member 300,alignment accuracy between the laser source 100 and the light modulationelement 200 is high.

In the projector 1000, the light transmissive member 300 disposed in thelight path between the laser source 100 and the light modulation element200 is a polarization element. Since a lens such as an lens array is notdisposed between the laser source 100 and the light modulation element200, it is possible to achieve the reduction in size, and further, it ispossible to adjust the polarization direction and the polarizationdegree of the light emitted from the laser source 100.

It should be noted that although not shown in the drawings, the lighttransmissive member 300 can be a phase compensation element, forexample, for conversing elliptically-polarized light intolinearly-polarized light, or can also have both of the phasecompensation element and the polarization element.

1.2. Modified Examples 1.2.1. First Modified Example

Then, a projector 1100 according to a first modified example of thefirst embodiment will be described with reference to the accompanyingdrawings. FIG. 5 is a diagram schematically showing a display device 10Rof the projector 1100 according to the first modified example of thefirst embodiment.

Hereinafter, in the projector 1100 according to the first modifiedexample of the first embodiment, the points in which the projector 1100is different from the projector 1000 according to the first embodimentdescribed above will be described, and the description of the points inwhich the projectors are substantially the same will be omitted. Thissimilarly applies to second through fifth modified examples describedlater related to the first embodiment.

In the projector 1000 described above, the laser source 100 and thelight modulation element 200 are bonded to the light transmissive member300 disposed in the light path between the laser source 100 and thelight transmissive element 200 as shown in FIG. 2 .

In contrast, in the projector 1100, the laser source 100 and the lightmodulation element 200 are bonded to each other as shown in FIG. 5 . Inthe illustrated example, the laser source 100 and the light modulationelement 200 are coupled to each other with the interface bonding. Itshould be noted that although not shown in the drawings, the lasersource 100 and the light modulation element 200 can also be coupled toeach other with an adhesive.

In the projector 1100, the laser source 100 and the light modulationelement 200 are bonded to each other. Therefore, it is possible toachieve reduction in size compared to when, for example, an opticalcomponent such as a polarization element is disposed between the lasersource 100 and the light modulation element 200. Further, since thedistance between the laser source 100 and the light modulation element200 is reduced, the spread of the light emitted from the laser source100 becomes smaller in the stage in which the light emitted from thelaser source 100 enter the liquid crystal layer of the light modulationelement 200, and thus, it is possible to efficiently illuminate thelight modulation element 200. It should be noted that when the lightemitted from the laser source 100 has a high polarization degree (linearpolarization degree), it is not required to dispose the polarizationelement on the incident side of the light modulation element 200.Therefore, in such a case, the present configuration is preferable.

It should be noted that the light modulation element 200 can also be atransmissive liquid crystal light valve of a so-called in-cell typeprovided with a polarization element inside. In this case, an inorganictype polarization element is preferably used as the polarizationelement.

1.2.2. Second Modified Example

Then, a projector 1200 according to a second modified example of thefirst embodiment will be described with reference to the accompanyingdrawing. FIG. 6 is a diagram schematically showing a display device 10Rof the projector 1200 according to the second modified example of thefirst embodiment.

In the projector 1000 described above, the light transmissive member 300is the polarization element as shown in FIG. 2 .

In contrast, in the projector 1200, the light transmissive member 300 isa radiator plate as shown in FIG. 6 . The radiator plate radiates theheat generated in the laser source 100. The thermal conductivity of theradiator plate is higher than the thermal conductivity of a member to bebonded to the second surface 304. Specifically, the thermal conductivityof the radiator plate is higher than the thermal conductivity of theopposed substrate 202. The material of the radiator plate is, forexample, sapphire. It should be noted that although not shown in thedrawing, it is also possible for the radiator plate to be coupled to theradiator fin 150, other radiator fins, or the like.

It is preferable for the thermal expansion coefficient of the lighttransmissive member 300 as the radiator plate to be close to the thermalexpansion coefficient of the second electrode 124 of the laser source100, and the thermal expansion coefficient of the opposed substrate 202.Thus, it is possible to weaken the stress generated in the laser source100 and the light modulation element 200 due to a difference in thermalexpansion coefficient.

In the projector 1200, the light transmissive member 300 disposed in thelight path between the laser source 100 and the light modulation element200 is a radiator plate. Since no lens is disposed between the lasersource 100 and the light modulation element 200, it is possible toachieve the reduction in size. Further, since it is possible to radiatethe heat generated in the laser source 100 with the radiator plate, itis possible to increase the emission efficiency of the laser source 100.

1.2.3. Third Modified Example

Then, a projector 1300 according to a third modified example of thefirst embodiment will be described with reference to the accompanyingdrawing. FIG. 7 is a diagram schematically showing a display device 10Rof the projector 1300 according to the third modified example of thefirst embodiment.

In the projector 1000 described above, the light transmissive member 300is the polarization element as shown in FIG. 2 .

In contrast, in the projector 1300, the light transmissive member 300includes a radiator plate 330 and a polarization element 332 as shown inFIG. 7 .

The radiator plate 330 has a first surface 302, and is bonded to thelaser source 100. The polarization element 332 has a second surface 304,and is bonded to the light modulation element 200. The radiator plate330 and the polarization element 332 are bonded to each other. In theillustrated example, the light transmissive member 300 has an adhesive334, and the radiator plate 330 and the polarization element 332 arecoupled to each other with the adhesive 334. The material of theadhesive 334 is the same as, for example, the adhesive 310 describedabove.

The radiator plate 330 radiates the heat generated in the laser source100 similarly to the radiator plate as the light transmissive member 300described in “1.2.2. Second Modified Example” described above. Thepolarization element 332 adjusts the polarization direction and thepolarization degree of the light emitted from the laser source 100similarly to the polarization element as the light transmissive member300 described in “1.1. Projector” described above.

It should be noted that it is possible for the light transmissive member300 to have the polarization element 332 on the laser source 100 side,and have the radiator plate 330 on the light modulation element 200side, but it is preferable to have the radiator plate 330 on the lasersource 100 side as shown in FIG. 7 from the viewpoint of heat radiationproperties. Further, although not shown in the drawing, it is alsopossible for the radiator plate 330 to be coupled to the radiator fin150, other radiator fins, or the like.

1.2.4. Fourth Modified Example

Then, a projector 1400 according to a fourth modified example of thefirst embodiment will be described with reference to the accompanyingdrawings. FIG. 8 is a diagram schematically showing a display device 10Rof the projector 1400 according to the fourth modified example of thefirst embodiment. FIG. 9 is a diagram schematically showing a radiatorplate 400 of the projector 1400 according to the fourth modified exampleof the first embodiment, and is a diagram viewed from the a proceedingdirection of the light emitted from the laser source 100.

The projector 1000 described above has the light transmissive member 300as shown in FIG. 2 . In contrast, the projector 1400 has the radiatorplate 400 as shown in FIG. 8 and FIG. 9 .

The radiator plate 400 is disposed between the laser source 100 and thelight modulation element 200. The radiator plate 400 radiates the heatgenerated in the laser source 100. The laser source 100 and the lightmodulation element 200 are bonded to the radiator plate 400.

The radiator plate 400 has a first surface 402 and a second surface 404.The laser source 100 is bonded to the first surface 402. The lightmodulation element 200 is bonded to the second surface 404. In theillustrated example, the first surface 402 and the second surface 404face to directions opposite to each other.

The radiator plate 400 is provided a through hole 410 through which thelight emitted from the laser source 100 passes. In the example shown inFIG. 9 , the radiator plate 400 has a frame-like shape. The radiatorplate 400 can also be bonded to an area other than the light emittingsection 100 a of the laser source 100 when viewed from the proceedingdirection of the light emitted from the laser source 100.

The material of the radiator plate 400 is, for example, kovar or copper.Alternatively, as the radiator plate 400, there can be used what isobtained by using a copper plate on the laser source 100 side and akovar plate on the light modulation element 200 side. Since the thermalexpansion coefficient around the room temperature of kovar is relativelysmall among metals, and is close to the thermal expansion coefficient ofhard glass or ceramics, it is possible to weaken the stress caused by adifference in thermal expansion coefficient between the radiator plate400 and the opposed substrate 202. Further, copper is higher in thermalexpansion coefficient compared to kovar, and can therefore efficientlyradiate the heat generated in the laser source 100.

In the projector 1400, the radiator plate 400 is provided the throughhole 410 through which the light emitted from the laser source 100passes. Therefore, it is possible to radiate heat generated in the lasersource 100 while preventing the light emitted from the laser source 100from being absorbed in the radiator plate 400. It should be noted thatalthough not shown in the drawing, it is also possible for the radiatorplate 400 to be coupled to the radiator fin 150, other radiator fins, orthe like.

1.2.5. Fifth Modified Example

Then, a projector 1500 according to a fifth modified example of thefirst embodiment will be described with reference to the accompanyingdrawing. FIG. 10 is a cross-sectional view schematically showing a lasersource 100 of the projector 1500 according to the fifth modified exampleof the first embodiment.

In the laser source 100 of the projector 1000 described above, thecolumnar parts 110 of the photonic crystal structure 108 each have thelight emitting layer 114 as shown in FIG. 4 .

In contrast, in the laser source 100 of the projector 1500, the columnarparts 110 do not have the light emitting layer 114 as shown in FIG. 10 .

In the projector 1500, the material of the columnar parts 110 is, forexample, Si-doped n-type GaN. The photonic crystal structure 108 isconstituted by the columnar parts 110, and gaps 111 each located betweenthe columnar parts 110 adjacent to each other. In the illustratedexample, there is disposed a taper part 113 with the diameter graduallyincreasing in an upward direction on each of the columnar parts 110. Thematerial of the taper part 113 is the same as that of the columnar part110. It should be noted that the taper parts 113 are not required to bedisposed.

The semiconductor layer 112 is disposed above the taper parts 113. Thelight emitting layer 114 is disposed on the semiconductor layer 112. Thesemiconductor layer 116 is disposed on the light emitting layer 114. Thefirst electrode 122 is disposed on the semiconductor layer 112. Thesecond electrode 124 is disposed on the semiconductor layer 116. In theprojector 1500, the light emitting section 100 a corresponds to thelight emitting layer 114. It should be noted that although not shown inthe drawing, it is also possible for the semiconductor layers 112, 116and the light emitting layer 114 to be disposed between the substrate102 and the photonic crystal structure 108.

When the photonic crystal structure 108 does not have the light emittinglayer 114 as in the projector 1500, the light leaked from the lightemitting layer 114 toward the photonic crystal structure 108 is confinedin a direction perpendicular to the stacking direction, and is emittedin the stacking direction.

2. Second Embodiment

Then, a projector according to a second embodiment will be describedwith reference to the accompanying drawings. FIG. 11 is a diagramschematically showing the projector 2000 according to the secondembodiment. FIG. 12 is a diagram schematically showing a display device10R of the projector 2000 according to the second embodiment.

Hereinafter, in the projector 2000 according to the second embodiment,the points in which the projector 2000 is different from the projector1000 according to the first embodiment described above will bedescribed, and the description of the points in which the projectors aresubstantially the same will be omitted.

In the projector 1000 described above, the light modulation elements 200are the transmissive type liquid crystal light valves for transmittingthe light emitted from the laser sources 100 as shown in FIG. 1 and FIG.2 .

In contrast, in the projector 2000 described above, the light modulationelement 200 is a reflective type liquid crystal light valve forreflecting the light emitted from the laser source 100 as shown in FIG.11 and FIG. 12 . The projector 2000 is an LCoS (Liquid Crystal onSilicon) projector.

In the projector 2000, the light transmissive member 300 is apolarization split element, and is specifically a polarization beamsplitter. The polarization beam splitter is an optical elementconfigured to sandwich a polarization split film 340 with tiltedsurfaces of a pair of rectangular prisms made of glass. The polarizationsplit element transmits specific linearly-polarized light, for example,P-polarized light with respect to the polarization split film 340, andreflects linearly-polarized light having the polarization directionperpendicular to the specific linearly-polarized light, for example,S-polarized light with respect to the polarization split film 340. Thepolarization split element spatially separates the illumination lightentering the light modulation element 200 and the image light emittedfrom the light modulation element 200 from each other using thisfunction.

The linearly-polarized light high in polarization degree is emitted fromthe laser source 100, and the polarization direction of thelinearly-polarized light is set so as to be P-polarized light withrespect to the polarization split film 340. The P-polarized lightemitted from the laser source 100 transmits through the polarizationsplit film 340 of the polarization split element, and enters the lightmodulation element 200. Since the polarized light which has a littlepossibility of existence and which is different from the P-polarizedlight is reflected by the polarization split film 340, the P-polarizedlight alone enters the light modulation element 200. The light havingentered the light modulation element 200 is converted into theS-polarized light due to the light modulation action to form the imagelight, reflected in the opposite direction to the direction at theincidence, and is then emitted from the light modulation element 200.The image light as the S-polarized light having been emitted from thelight modulation element is reflected by the polarization split film340, and is then emitted from the polarization split element with theproceeding direction folded as much as 90°.

In the projector 2000, the light transmissive member 300 disposed in thelight path between the laser source 100 and the light modulation element200 is the polarization split element. Since no lens is disposed betweenthe laser source 100 and the light modulation element 200, it ispossible to achieve the reduction in size. Further, due to thepolarization split element, it is possible to split the light emittedfrom the laser source 100 into, for example, the P-polarized light andthe S-polarized light.

3. Third Embodiment

3.1. Projector

Then, a projector according to a third embodiment will be described withreference to the accompanying drawings. FIG. 13 is a diagramschematically showing the projector 3000 according to the thirdembodiment.

Hereinafter, in the projector 3000 according to the third embodiment,the points in which the projector 3000 is different from the projector1000 according to the first embodiment described above will bedescribed, and the description of the points in which the projectors aresubstantially the same will be omitted.

In the projector 1000 described above, the light modulation element 200is the transmissive type liquid crystal light valve for transmitting thelight emitted from the laser sources 100 as shown in FIG. 2 .

In contrast, in the projector 3000, the light modulation element 200 isa DMD (Digital Micromirror Device; registered trademark) for reflectingthe light emitted from the laser sources 100 as shown in FIG. 13 . TheDMD is a light modulation element provided with a number of micromirrorsand controlling the emission direction of the reflected light byindividually turning the micromirrors. The projector 3000 is a DLP(Digital Light Processing; registered trademark) projector.

In the projector 3000, the light transmissive member 300 has a coloredlight combining prism 350 and a total-reflection prism 352.

Laser sources 100R, 100G, and 100B are bonded to the colored lightcombining prism 350. In the illustrated example, the laser sources 100R,100G, and 100B are bonded to the colored light combining prism 350 withthe adhesive 310. The laser source 100R emits the red light similarly tothe laser source 100 of the display device 10R shown in FIG. 1 . Thelaser source 100G emits the green light similarly to the laser source100 of the display device 10G shown in FIG. 1 . The laser source 100Bemits the blue light similarly to the laser source 100 of the displaydevice 10B shown in FIG. 1 .

The colored light combining prism 350 combines the light emitted fromthe laser source 100R, the light emitted from the laser source 100G, andthe light emitted from the laser source 100B with each other similarlyto the colored light combining prism 30 shown in FIG. 1 .

In the example shown in FIG. 13 , the light transmissive member 300 hasan adhesive 354, and the total-reflection prism 352 is coupled to thecolored light combining prism 350 with the adhesive 354. The adhesive354 is, for example, the same adhesive as the adhesive 310.

The total-reflection prism 352 has a first prism 352 a and a secondprism 352 b made of glass, and the first prism 352 a and the secondprism 352 b are integrally fixed via a spacer 353. Between the firstprism 352 a and the second prism 352 b, there is disposed an air gap G.The light emitted from the colored light combining prism 350 enters thefirst prism 352 a, and is then totally reflected by the air gap G toenter the light modulation element 200. The light modulation element 200is coupled to the total-reflection prism 352 with the adhesive 310. Thelight modulated in the light modulation element 200 is transmittedthrough the total-reflection prism 352, and then enters the projectionlens 40.

In the projector 3000, since the light transmissive member 300 disposedin the light path between the laser source 100 and the light modulationelement 200 has the colored light combining prism and thetotal-reflection prism, and no lens is disposed between the laser source100 and the light modulation element 200, the reduction in size can beachieved.

Further, when illuminating the light modulation element 200, the lightenters the light modulation element 200 from an oblique direction withrespect to the normal line of the display area 200 a of the lightmodulation element 200. In this case, the upper surface of the lightemitting section 100 a of the laser source 100 and the display area 200a are in a nonparallel arrangement relationship. Therefore, even whenthe light emitting section 100 a has the same rectangular shape as thatof the display area 200 a when viewed from the stacking direction, theillumination area in the display area 200 a is deformed into anon-rectangular shape. Therefore, it is preferable to adopt the shapeand the size of the light emitting section 100 a taking the deformationof the shape of the light in the oblique illumination into considerationwhen viewed from the stacking direction as shown in FIG. 14 . It shouldbe noted that FIG. 14 is a diagram schematically showing the lasersource 100 from the proceeding direction of the light emitted from thelaser source 100. Further, in FIG. 14 , the laser source 100 issimplified, and the display area 200 a of the light modulation element200 is also illustrated. It should be noted that the matters describedabove are also applied to a projector 3100 described later.

3.2. Modified Examples

Then, a projector according to a modified example of the thirdembodiment will be described with reference to the accompanying drawing.FIG. 15 is a diagram schematically showing the projector 3100 accordingto the modified example of the third embodiment.

Hereinafter, in the projector 3100 according to the modified example ofthe third embodiment, the points in which the projector 3100 isdifferent from the projector 3000 according to the third embodimentdescribed above will be described, and the description of the points inwhich the projectors are substantially the same will be omitted.

The projector 3000 described above has the three laser sources 100R,100G, and 100B as shown in FIG. 13 .

In contrast, in the projector 3100, there is provided a single lasersource 100 as shown in FIG. 15 . The light emitting section 100 a of thelaser source 100 has three types of parts which are different inemission wavelength from each other, and light emission of which canindependently be controlled. Further, each of the three types of partshas, for example, a plurality of sub-light emitting sections each havinga size of several tens of micrometers, and those sub-light emittingsections are regularly arranged in a plane. By the sub-light emittingsection emitting light, the three types of parts respectively emit thered light, the green light, and the blue light. The laser source 100emits the three types of light in a time-sharing manner. Further, in theprojector 3100, the light transmissive member 300 is thetotal-reflection prism.

It should be noted that the light emitted from the laser source 100 hasa radiation angle which is not 0°, but extremely small, and is slightlydiffused. Therefore, the sub-light emitting sections adjacent to eachother for emitting the light the same in color in the laser source 100are disposed at a distance of, for example, several tens of micrometers,but the light emitted from the sub-light emitting sections adjacent toeach other is moderately mixed in the stage of entering the lightmodulation element 200. Therefore, it is possible to evenly illuminatethe display area 200 a of the light modulation element 200.

In the projector 3100, the light transmissive member 300 disposed in thelight path between the laser source 100 and the light modulation element200 is the total-reflection prism. Since no lens is disposed between thelaser source 100 and the light modulation element 200, it is possible toachieve the reduction in size.

The present disclosure can be implemented with some of the constituentsomitted, or combining any of the embodiments and the modified exampleswith each other within a range in which the features and the advantagesdescribed in the specification are provided.

The present disclosure is not limited to the embodiments describedabove, but can further variously be modified. For example, the presentdisclosure includes substantially the same configuration as theconfigurations described in the embodiments. Substantially the sameconfiguration denotes a configuration substantially the same in, forexample, function, way and result, or a configuration substantially thesame in object and advantage. Further, the present disclosure includesconfigurations obtained by replacing a non-essential part of theconfiguration explained in the above description of the embodiments.Further, the present disclosure includes configurations providing thesame functions and the same advantages or configurations capable ofachieving the same object as that of the configurations explained in thedescription of the embodiments. Further, the present disclosure includesconfigurations obtained by adding a known technology to theconfiguration explained in the description of the embodiments.

What is claimed is:
 1. A projector comprising: a laser source includinga light emitting section; a light modulation element configured tomodulate light emitted from the laser source in accordance with imageinformation; and a frame disposed between the laser source and the lightmodulation element, wherein the frame includes: a first surface that iscoupled to the laser source; and a second surface that is coupled to thelight modulation element, the laser source includes: a substrate; and alaminated structure provided to the substrate, and having a lightemitting layer configured to emit light, the laminated structureconstitutes a photonic crystal structure configured to confine the lightemitted by the light emitting layer in an in-plane direction of thesubstrate, and emit the light emitted by the light emitting layer in anormal direction of the substrate, and the first surface of the frame iscoupled to the light source in an area other than an area where thelight emitting section is provided when viewed from the normal directionof the substrate.
 2. The projector according to claim 1, wherein thelaser source and the first surface are bonded to each other withinterface bonding.
 3. The projector according to claim 1, wherein thelight modulation element and the second surface are bonded to each otherwith interface bonding.
 4. The projector according to claim 1, whereinthe laser source and the first surface are bonded to each other with anadhesive that includes a metal filler.
 5. The projector according toclaim 1, wherein the light modulation element and the second surface arebonded to each other with an adhesive that includes a metal filler.